Summary: On­line Load Balancing \Lambda
Yossi Azar y Andrei Z. Broder y Anna R. Karlin y
Abstract
The setup for our problem consists of n servers that must complete a set of tasks.
Each task can be handled only by a subset of the servers, requires a different level of
service, and once assigned can not be re­assigned. We make the natural assumption
that the level of service is known at arrival time, but that the duration of service
is not. The on­line load balancing problem is to assign each task to an appropriate
server in such a way that the maximum load on the servers is minimized. In this
paper we derive matching upper and lower bounds for the competitive ratio of the
on­line greedy algorithm for this problem, namely (3n) 2=3
2
(1 + o(1)), and derive a
lower
bound,\Omega\Gamma n 1=2 ), for any other deterministic or randomized on­line algorithm.
1 Introduction
Consider an idealized local area network that links multi­media workstations, com­
puters, I/O devices, etc. Each device is directly connected to one or more gateways
(bridges) to the net. Communication tasks arrive and disappear at arbitrary times.
Upon arrival, each task requests a certain guaranteed bandwidth (e.g. low for file

Source: Azar, Yossi - School of Computer Science, Tel Aviv University

Collections: Computer Technologies and Information Sciences